Electrically operated apparatus for railway signaling and the like



Jan. 19, 1932. 1 L. H. PETER ETAL A 1,842,046

ELEGTRICALLY OPERATED APPARATUS FOR RAILWAY SIGNALING AND THE LIKE Filed Feb." 18, 1928 INVENTQRS'. J L-H.Pe,ter; a I R..S.Rbbott,

Patented Jan. 19, "1932 umreosmres PATENT orrlcs LESLIE H. PETER AND REGINALD S. ABBOTT, OF LONDON, ENGLAND, ASSIGNOB-S. BY IESNE ASSIGNMENTS, TO THE UNION SWITCH A" SIGNAL COIPANY; 0! SWISSVALE, PENNSYLVANIA, A CORPORATION OF FEN'NSYLVANIA ELEGTRICALLY OPERATED APPARATUS FOR RAILWAY SIGNALIN AND THE LIKE i Application med I'ebruary I8, 1928, Serial No. 255,469, and in Great Britain February 28, 1927.

Our invention relates to electrically operated apparatus for railway signaling and the like, and has for its object to provide improved arrangements whereby the unintentionul operation of the apparatus by extraneous current may be effectively prevented.

Our invention is particularly, although not exclusively applicable to signaling systems comprising block or token instruments located at each end of a, block section, the in struments being connected by a line conductor for transmitting signaling or controlling current "from one instrument to the other in the well-known manner.

in such systems it is of primary importunes to protect the block or signal instruments from undesired operutionloy extrane' one current entering the line conductor due for instance to eccidentcl contact of this conductor with en external source of current, and various arrangements hnve previously been proposed for protecting the system in this respect by utilisin u signal or controlling current of distinctive character and rendering the instruments responsive only to such current.

According to the present invention the current transmitted to the electrically operated apparatus to be protected is a pulsating uni directional current, the a paratus being so constructed as to be unu ected by constant or non-pulsating unidirectional current, and

may, furthermore, if desired, be of the polar-; ized type so as to be differently affected in accordance with the direction or sign of the pulsating unidirectional current transmitted to the apparatus.

()ur invention is illustrated by way of ex ample in the accompanying drawings, Fig. 1 of which is a diagrammatic view showing the invention as applied to a pair of electrically controlled token. instruments for controlling trafiic through a block section of a single line railway.

, Fi 2 is a similar view somewhat simplified i ust-rating'the eifect of extraneous curs rententering the line, conductor connecting the two token instruments.

Figs. 3 and 4 are views of modified forms of transmitting apparatus which may be employed in the system of Fig. 1, Figs. 5 and 6 are diagrammatic views showingalternative arrangements of portions of the apparatus shown in Fig. 1.

Referring now first to Fig. 1 the token in- '-struments not shown are assumed to be lowith arrangements for transmitting a unidi; 'rectional pulsating current to the other 1nstrument along the line conductor 1 comprising a primary or secondary battery 3, the ter minels of which are connected to the line conductor 1 through a current interrupter, a cut out switch *3 end a reversing switch 7. The current interrupter is shown in the form of an electromegneticnlly operated vibrating device, for converting the direct current from the battery 3 into a unidirectional pulsating current, and comprises an electro-magnct 4 the. armature 5 of which normally tends to complete a circuit from the battery 3 through the elcctro-magnet 4: when the switch 6 is closed. The resultant energization of the electro mugnet 4i causes the armature 5 to interrupt this circuit so that the armature 5 is alternately attracted and released. The ri ht hund terminal of the battery 3 is thus, w on the switch 5 is closed, alternately connected to and disconnected from the central contacts of the reversing switch 7 and by setting the latter into one or other of its two operative positions a pulsating unidirectional current of normal or reverse sign or polarit is transmitted to the line conductor 1. e end of the line conductor 1 at B is connected through the primary winding 9 of a transformer 8 and a condenser 32 to the earth connection 2, the secondary winding 10 of the transformer 8 being connected through a current rectifiing device 11 preferably of the copper ox e type to the terminals of a direct current relay 12. The, latter, when ener 'zed by the unidirectional current supplied rom the rectifier 11 is arranged to close contact 13 thereby completing a circuit from the line conductor 1 through the energizing winding 14 of a polarized relay 15 to earth, the contacts of the relay 15 being connected to the lock magnets or other controlling devices of the token instrument at B in the usual manner. v

In operation, it will be understood that the unidirectional pulsating current transmitted from A through the line conductor 1 passes through the primar winding 9 of the transformer 8 at the B en of the section and is converted into alternating current in the secondary winding 10 of the transformer. This alternating current is converted intounidirectionalcurrent in the rectifier 11 and energizes the direct current relay 12 the contact 13 of which is thereby closed to complete a ,circuit from the line conductor 1 through the polari zed relay winding 14. It will be a preci-- ated thatsince the direct current re ay 12 must be energized to closethe contact 13 included in the circuit of the polarized relay 15 a continuous current traversing the line wire 1 will fail to energize the direct current a relay 12 owing to the presence of the transformer 8, while at the same time by suitably setting the reversin switch 7 at the A end of the section the po arized relay 15 will be caused to respond difierentl according to the I sign or direction of the uni irectional current supplied to the line conductor 1. v It will be observed that the electro-magnet 4 of the vibrating device is included in a local circuit supplied with operating current from the battery 3 so that the current transmitted to the line conductor 1 may be relatively small, this arrangement also providin additional protection against the effect 0 extraneous current as will be understood from a consideration of Fig.2.

If an earthed source X of extraneous direct current is applied to' the line conductor 1 as shown in F1 2, the current from this source would not 0 itself effect the operation of the receiving apparatus owing to the presence of the transformer 8.

If, however, the source X were connected to the line conductor 1 while the transmitting apparatus indicated at A was being operated, the resulting effect would depend upon whether the current from the source X was of the same or o posite polarity to the current being supplied to the conductor from the batter 3.

In the ormer case, the extraneous current would obviously assist the normal current and would not have any dangerous effect upon thelreceivin apparatus at B although t might weaken t e operation of the current nterrupter. If, however, the polarity of the extraneous current from the source X is opposite to that of the normal current supplied from the battery 3 as shown in Fig. 2 in which the direction of the normal current is shown in full line arrows and that of the extraneous current in dotted-arrows, it will be seen that the extraneous current while tending to reverse the current transmitted to the receiving apparatus at B tends to strengthen the adjusted that any extraneous current which might be suflicient to cause the reverse operation of the receiving a paratus atB will cause the armature 5 of t e current interrupter to be held in its attracted position so that pulsating current is not supplied to the line conductor 1 from the battery 3 and the recgiving apparatus at B is thus not oper- If desired the battery 3 and current vibrator utilized as a source of unidirectional pulsating current for transmission to the line conductor 1 may be replaced by a hand or foot-operated dlrect current generator .the commutator of which is provided with a suitable number of se ents. Transmitting apparatus of this kin is illustrated in Figs. 3 and 4 in which a hand-operated generator is indicated at 16;

.Referring now to Fig. 3 it will be seen that a cut-out relay 17 is provided for protection against extraneous currents, the rela 17 being provided with two windings 1 19 and two armatures 20, 21.

The reversing switch 7 is provided with an additional contact arm-22 connected to one terminal of the relay winding 18, the other terminal of this winding being connected to the relay armature 20. A local battery 23 is provided oneterminal of which is connected to the terminal 24 of the genera tor 16, the other terminal of the battery 2?. being connected to the front contact'of the rela armature 20.

The other terminal 25 of the generator 16 is connected through the relay winding 19 to the relay armature 21 the back contact of which is connected to the central contacts of the reversing switch 7. The relay armature 21 is provided with a bridging contact so that circuit leading from the relay winding 19 to the reversing switch 7 is not broken when 1 through the relay winding 19, the relay armature 21 and the reversing switch 7 the setting of this switch determining the 0- 'larity of the current transmitted to the line conductor 1.

extraneous current were being applied to the line conductor 1, the armatures and 21 will be moved to their attracted positions so that a local circuit through the relay winding 18 will be completed from one terminal of the battery 23 through the relay armature 20, the winding 18 and contact arm 22 to the other terminal of the battery 28.

' The upward movement of the relay armature 21 eventually interrupts the connection of the generator 16 tothe line conductor after the local circuit above described has been completed and the transmission of unidirectional pulsating current to the line conductor is thus prevented so long as the relay -17 remains energized. This relay is deenergized when the reversing switch 7 is set into its inoperative position (shown in Fig. 3) owing to the interruption of the local circuit from the battery 23 at the contact arm 22.

Referring now to the modified arrangements shown in Fig. 4, the cut-out relay 17 is in this case only provided with a single'winding a choke coil 26 being provided in .the circuit leading from the terminal 25 of the generator 16 through the relay '17 to the reversing switch 7. The choke coil 26 is however arranged to be short circuited by the relay armature 21 so long as the relay 17 is deenergized.

Under normal conditions the generator 16 being operated, supplies unidirectional pul sating current to the line conductor 1 through the winding of the relay 17 and the armature 21, this current being insufficient to move the armature 21 from its unattracted position.

In the event however of the relay 17 becoming energized due to extraneous current in the line conductor 1 the armatures 20, 21 are attracted.

The upward movement of the armature 20 under these conditions serves to connect a condenser 27 directly across the terminals of the generator 16 while the upward movement of the armature 21 causes the choke-coil 26 to be included in the circuit from the generator 16 tothe reversing switch 7. The condenser 27 and the choke-coil 26 both tend to prevent the pulsating current from the generator 16 reaching the line conductor 1 so that so long as the relay 17 is energized unidirectional pulsating current is not transmitted to operate the receiving apparatus at B.

Again in a further modification the electromagnetically operated current interrupter as indicated at 4, 5 in Figs. 1 and2 may be replaced by any other device capable of converting direct current into unidirectional pulsating current, such, for instance, as a neon tube, indicated at 28 in Fig. 5, the electrodes 29, 30 of this tube being shunted by a condenser 31. Again,.in'a furthermodification the rectifier 11 at the receiving end of the section may be dispensed with, as shown in Fig. 6, the relay 12 operated by current from the secondary winding 10 of the transformer 8 being an alternating current relay adapted when energized to close the circuit of the polarized relay winding 15 in the manner above described.

Our invention is evidently not limited to the particular arrangements and connections above described which may be varied in many respects without exceeding the scope of the invention.

Having now particularly described and ascertained the nature of our said invention and in what manner the sameis to be performed, we declare that What we claim is 1. In combination, a line conductor extending between a first and a second location, :1.

source of energy at the first location, a transformer at the, second location, a condenser at the second location a circuit including said line conductor, said source, the primary of said transformer, and said condenser; means for periodically interrupting the current supplied to said circuit from said source, a first relay at the second location connected with the secondary of said transformer, and a second relay at the second location connected in multiple with said condenser over a front contact of said first relay.

2. In combination, a line conductor extending between a first and a second location, a

first location having one terminal connected with ground and the other terminal connected with said conductor, a condenser at the second location having one plate connected with ground, a transformer at the second lolocation connected in multiple with said con-.

denser over a front contact of said first relay.

3. In combination, a line conductor extending between a first and a second location, an electromagnetica-lly operated current interrupter at the first location, a source of unidirectional current, a reversing switch for reversibly connecting said source and said interrupter in series with ground and with said conductor, a polarized relay at the sec ond location having one terminal connected with ground, a second relay at the second source of periodically varying current at the ondary of said transformer, and a condenser connected in multiple with said contact and said olarized relay in serles.

4. n combination, a line conductor extending between a first and a second location, a

source of pulsating unidirectional current at the first location, a condenser at the second location, a transformer at the second location; a circuit including said source, said conductor, said condenser, and the primary of said transformer; a first relay at the second location connected with the. secondary of said transformer, a second relay at the second location connected in multiple with said condenser over a front contact of said first relay, and means at the first location for decreasing the current supplied to said circuit from said. source to a value which is insuflicient to energiae said first relay if extraneous direct current having a value sufiicient to operate said second relay is supplied to said circuit.

5. In combination, a line conductor ex.- tending between a first and a second location, a source of pulsating unidirectional current at the first location, a condenser at the second location, a transformer at the second location; a circuit including said source, said conductor, said condenser, and the primary of said transformer; a first relay at the second location connected with the secondary of said transformer, a second relay at the second location connectedin multiple with said condenser over a front contact of said first relay, a third relay at the first location interposed in said circuit and energized if extraneous direct current exceeding a predetermined value is supplied to said conductor, a second condenser at the first location connected in multiple with said source over a front contact of said third relay, and a choke coil at the first location shunted over a back contact of said third relay and interposed in said circuit when said third relay is energized.

6. In combination, a manually controlled source of pulsating unidirectional current, a condenser, a winding, a circuit for said wind mg including said source and said condenser, a rectifier, a first relayreceivin ener from sa1d winding through said recti or on y when current from said source is flowing in said circuit, a second relay connected in multiple with said condenser over a front contact of said first relay, and means for disconnecting said source from said circuit if the current in said circuit-exceeds a predetermined value.

7 In combination, a line conductor extending between a first and a, second location, a source of unidirectional current at the first location having one terminal connected with ground and the other terminal connected with said conductor, means including a neon tube at the first location for periodically interrupting the current supplied by said source, a condenser at the second location having one plate connected with ground, a transformerat the second location having its primary connected between said conductor and the other plate of said condenser, a first relay at the second location connected with the secondary of said transformer, and a second relay at the second location connected'in multiple with said condenser over a front contact of said first relay.

8. In combination, a line conductor extending between a first and a second location, a source of periodically varying current at the first location having one terminal connected with ground and the other terminal connected with said conductor, a condenser at the second location having one plate connected with ound, a transformer at the second location iaving its primary connected between said conductor and the other plate of said condenser, a first relay at the second location connected with the secondary of said transformer, a second relay at the second location connected in multiple with said condenser over a front contact of said first relay, and means at the first location for disconnecting said source from said conductor if dangerous extraneous currents are supplied to said conductor.

In testimony whereof we affix our signatures'.

mS LIE IETER. REGINALD S. ABBOTT. 

